The objectives of the Nutrition Core are to consolidate resources and provide support needed for adequate nutrition, body composition and physical activity assessment in the associated projects, and to conduct research required for continuing refinement of related methodology appropriate to cancer prevention control projects. Specific aims include 1) supervision of the design and collection of all dietary and physical activity data in close collaboration with the Adherence Core; 2) Maintenance and ongoing development of appropriate food composition data bases; 3) Reduction of dietary data (coding and conversion to nutrients, food groups, or compounds of interest; 4) Provision of data to project investigators, working in close collaboration with the Biometry Core; 5) Consultation with project investigators regarding interpretation of results; 6) Maintenance of quality control procedures for dietary and physical activity, data collection, coding, and analysis; and 7) Methodologic investigation in support of the projects. The two colon cancer prevention intervention projects (Fiber, Ursodeoxcholic Acid) included in this application require ongoing nutritional status and dietary assessment components for eligibility, and to evaluate confounding and interacting nutrients. Dietary and physical activity data will be collected to monitor time trends, and to assess their relation to polyp recurrence. The Genetic Alterations study will require dietary intake assessment data and analysis in support of specific aims regarding the relation of diet to genetic alterations In polyps. The common focus on colon polyps and the design of the three projects permit consolidation of efforts regarding dietary evaluation and physical activity, and will permit cross-project analyses which will extend the utility of each project's results. A working framework in the form of a proposed model for nutrient interactions with the promotion and progression of small adenomas has been developed to guide the collection and analysis of dietary data. The Arizona Food Frequency Questionnaire and dietary intake records will be used to determine eligibility and monitor subjects in the projects. A scannable physical activity questionnaire, developed from our current questionnaire, will be used to monitor activity patterns throughout the trials.